Fix TestAarImportProducesJniPackages/aar-no-jni

TestAarImportProducesJniPackages was attempting to assert that an
aar_import module always had a JniPackageProvider, but was instead
asserting that the return type was always a JniPackageInfo.  Since
ModuleProvider returned the zero value of JniPackageInfo even when
there was no provider that was always true.

Fix aar_import to always set JniPackageProvider.

Test: TestAarImportProducesJniPackages
Change-Id: Idaf106e14373490d4eb807892e174aaaf094bbcf
diff --git a/java/aar.go b/java/aar.go
index af99cd0..aca73aa 100644
--- a/java/aar.go
+++ b/java/aar.go
@@ -1256,11 +1256,11 @@
 				},
 			})
 		}
-
-		ctx.SetProvider(JniPackageProvider, JniPackageInfo{
-			JniPackages: a.jniPackages,
-		})
 	}
+
+	ctx.SetProvider(JniPackageProvider, JniPackageInfo{
+		JniPackages: a.jniPackages,
+	})
 }
 
 func (a *AARImport) HeaderJars() android.Paths {